Two systems for reinforcing "in-service" orthotropic bridge decks (OBDs) have been researched: the bonded steel plates system and the sandwich steel plates system. The main idea of these types of reinforcements is to stiffen the existing deck plate, thereby reducing the stress at the fatigue-sensitive details, and thus extending the fatigue life of the OBD. Both reinforcement systems consist of adding a second steel plate to the existing steel deck. The behaviour and the effect of the reinforcement systems on full-scale OBD are investigated. Full-scale static tests and finite element analyses were performed on reinforced deck panels, using realistic wheel loads. The results showed at least 40% of stress reduction close to the fatigue-sensitive details after applying both reinforcements. The two suggested reinforcement systems showed a good performance and proved to be efficient lightweight solutions to refurbish orthotropic bridge decks anDextend their life span.